BEIJING (AP) — A strong earthquake has jolted China’s Central Asian frontier, shaking buildings and cutting off electricity in the remote mountainous area and sending rescuers in search of casualties.

The U.S. Geological Survey measured the Saturday morning quake that hit the Xinjiang region at 6.3 magnitude, while China’s Earthquake Networks Center put it at 6.6.

China’s state-run Xinhua News Agency reported residents near the epicenter were shaken out of bed in pre-dawn darkness and that some households lost electricity. It reported that the quake shook buildings 120 miles to the west in the regional capital, Urumqi.

Xinhua said rescuers are being dispatched to the sparsely populated area to search for casualties.